Hi all. I have an 04 Chevy Venture. Recently it started making what I can only describe as a grinding. I have been a mechanic for over 30 years, working on everything from motorcycles to heavy construction equipment. This is a new one on me. I have checked the wheel bearings, brakes and rotors, and suspension. All good. I have blocked her up and put it in gear, and the noise seems to be coming from the transaxle. Fluid is cherry red and is not burnt, no metal shavings, and not low.
I have noticed that while driving, if I jog the wheel left or right, it quite until you straighten out again. If I weave back n forth going down the road, it’s pretty much non existant, but the cops are starting get suspicious. LOL
Any suggestions?
Thanks
Any difference in gear vs coasting in neutral at the same speed?
"if I jog the wheel left or right, it quite [it’s quiet] until you straighten out again"
Could the power steering pump be making noise unless it’s under load?
No difference between coasting in neutral or under power.
And power steering pump is fine, no noise from it.
This is front wheel drive, right? hmmm … those are indeed unusual symptoms. I can offer a wild guess. On some automatic transmission designs the transmission fluid and the differential fluid are in different places, and sometimes aren’t even the same fluid types, so my wild guess is your tranny fluid is ok, but the differential fluid is the problem. That could cause a change in the sound it makes b/c the differential uses its gears differently when turning vs going straight.
In spite of the fact that you have checked the wheel bearings . . .
to me, this sounds like a classic case of bad wheel bearings
Just out of curiosity, what makes you sure the wheel bearings are okay?
When in doubt, I hook up chassis ears and go for a road test. I’ve found many bad wheel bearings that way. And they didn’t have any play whatsoever
“I have noticed that while driving, if I jog the wheel left or right, it quite until you straighten out again.”
THAT is why it sounds like bad bearings to me. Based on what YOU wrote. I’ve replaced many bad bearings, and the symptoms were IDENTICAL to yours
I guess I would have expected the contrary to @db4690 if both wheel bearings are kaput. My idea is that turning shifts most of the weight of the car to one side of the car, so that side should make even more noise compared to when going straight. If both front wheel bearning are bad, zig sagging down the road should cause an alternating noise pattern, right side, left side, etc.
That, and that the OP is a pro mechanic and has already checked the wheel bearings and says instead the noise seems to be coming from the transaxle makes wheel bearing as a cause unlikely. That’s my thinking and guessing anyway.
There’s many other possibilities of course. If the grinding noise isn’t actually from inside the transaxle, next guess would be the inner CV joint. After that the outer CV joint. If the ball bearings are just sliding along instead of rolling, that would make a scraping noise. The problem w/this theory is that I don’t think the CV joint ball bearings are rolling when the car is going straight.